Synchronizing device



Nov. 26, 1935. g, A, THOMP QN 2,022,095

SYNCHRONIZING DEVICE 2 Sheets-Sheet 1 Filed June 20, 1950 6521 ZA+Z 2 {Edgy/fly, I

WfiW' W athom) I Nov. 26, 1935. E, TH 2,022,095

SYNCHRONI ZING DEVICE 2 Sheets-Sheet 2 Filed June 20, 1930 friction and toothed'elements being easily angularly displaceable by axially directed pressure PatentedNov. 26, 1935 I a to General Motors Corporation, Detroit, Mich,

a corporation of Delaware Application June 20, 1930, Serial No. 462,510

12 Claims. (Cl. 192-53) The invention disclosed herein relates to trans.- mission mechanisms comprising two,, coaxial power transmitting membersrespectively providied with'tootheddriving elements adapted'tobe intermeshed whereby one member, may be 'posi tively driven from the other, and also provided, respectively, with frictionally engageable ele:

ments adapted to be coupled in order to bring the power transmitting members to equal speeds prior driving elements; The invention is animprovement over that dis-.

to intermeshing the positive closed in myapplication Serial No.,302,228 flied August 27, 1928, and is "particularly designed for motor vehicle transmissions although adapted for use with any variable speed gearing.

The chief object of the invention is to. oppose movement of thejtoothed elements into contact while the' power trans ittingjmembers to be coupled' are rotating asynchronously and simultaneously to promote synchronization by causing a detent onone of a pair of friction elements to be interposed in the. pathgof. movement of one of the toothed elementstoward theotherinreby the differential rotation of said power transmitting elementasaid spcnse to force vapplied against the detent .whensaid force due to differ-. ential rotation disappears; i. e. when the rotation of said two power transmitting members becomes synchronous;

. I In the accompanying drawings wherein like reference characters indicatelik'e parts throughout' the, several views:

Fig. l is, a section thru a motor vehicle gear box. or casing andinclosed gear tr ar'ismission showing'the main clutch shaft and spline shaft gears in section; j

Fig. 21s a cross section on line 2-1 of l; I

Fig-3 is across sectionon line 3-3 of Fig. 1; Fig.4 is a fragment illustrating schematically the position of a friction clutch element with respect to the movable. element of the. positive clutch when the power transmitting members.

are in asynchronous rotation;

Fig. 5 iso. fragment. illustrating schematically the same parts in position to permit intermesh-' ing of'the positive clutch elements when the transmission members are in synchronous rotationQ c I j Fig. 6 is a fragmentary perspective viewof :a

friction and'positive clutch element when ro-..

tation of the power transmission, members is asynchronous.

l gage a notch '63 in '7 is a view partly in transverse section illustrating a modification;

Fig. 8 is a fragmentary longitudinal section of the modified structure on line 8-8 of Fig. '1, and

Fig. 9 is a perspective view of an annular spring ada tedto press the-cooperating friction.- clutch elements lightly together.

In; said drawings. Sliindicates the body of the gear box, 52, the cover thereof, and. 53a hollow conical riser from thecover having on its upper end, as usual, a bearing for theball joint 54 of ahandleverSS for shifting gears inorder to, change the-ratio of the transmission betweenengine anddriving axle. Numerals 56 and 511' represent slide beeringhangers each perforated 1 to receive theparallel slidable shift rods =58 and. 59; rod. 58', which is in front. viewedas in Fig. .1, having been brokenaway to disclose the rod 80 behind it. Either. of .the shift rods may be en-..

gaged by handshift lever 55 and caused to move 1.

longitudinally in either direction in the usual manneras predetermined by the operator toex-v ecute his intention to change the speed ratio by mechani mv to be described. The variable speed.- mechanism illustrated has a capacity of speeds forward and onereverse. The shiftrod 59 carries a yoke ill by which the gearing may be adjusted to direct drive or intermediatespeed ratio, while the rod 58 carries a'yoke 8| adapted so to adjust the gearing to low or reverse.

The shift rods and hand lever described-are quite conventional except for the form of the yoke 60 and its connection with the hand lever.

- The lower end 62 of lever 55 is adapted to enshift rod 5:; but said'lower end 62 is notv coupled similarly to rod when said rod 59 is selectedto be shifted because. for reasons that willlater appear, the parts moved i by the latter rod have a shorter range of movew ment and require a greater forceto be applied. Accordingly yoke .60 is provided with a rigid arm 64 having in its upperend a notch 65 opentoward the .lever 55, while the latter is provided with a lug 66 adapted to be interlocked with said notch when the parts are in neutral position.

,As; the connectionbetween hand lever 56 and yoke. I is nearer to o the fulcrum ot the hand lever than the connection between saidlever and shift rod It a greater mechanical'advantage is 50 ed in shifting into .highand' intermediate than in shifting into low and reverse. I Gear casing II is provided with alined bearings 01 and 6! and with alined seats 6! and II. Bearing 01 carries the power delivery end of the main 55 three 1| while the remaining 7 box must be adjusted to an idle relation ineffecpower transmitting member which, as shown, is the 'main clutch shaft 1| of a motor vehicle. Bearing 68 supports a main driven member which, as shown, is the so-called spline shaft 12 of a motor vehicle transmission, which connects with the propeller shaft by a universal driving joint not shown. The front end 13 of the spline shaft power delivery end of the main clutch shaft. A fixed shaft 15 has its opposite ends supported in the seats 69 and 10. Sleeved on shaft 15 is a hollow countershaft rigidly connected to four gears as shown.

Drive gear 11 rigid with the power delivery and of shaft 1| is in constant mesh with gear 18 on the counter shaft. Gear 19 (one of the intermediate speed gears) mounted so that it may rotate freely on a bushing that is keyed to the spline shaft and locked against longitudinal movement thereon, is in constant mesh with gear 8| on the counter shaft. Gear 82 is slidable upon the spline shaft and controlled in its sliding movements by said yoke 6|. When moved forward gear 82 may be meshed with counter shaft gear 83 to adjust for low speed forward; when moved rearward it may be meshed with the reverse idler (not shown) which latter is in constant mesh with countershaft gear 84 as is customary.

In order to adjust the transmission train to direct drive or high speed ratio, spline shaft 12 must be positively coupled with main clutch shaft gears within the gear tive to transmit power. The means for coupling in direct drive comprise a positive dog or toothed clutch element 85 rigid with shaft 1| and a positive cooperating dog or toothed clutch'element 86 driven by or non-rotatable with respect to but slidable on the spline shaft 12.

nal gear-like teeth 81, while clutch element.86

is provided with counterpart external teeth 88 adapted to fit nicely within the cavity of clutch element 85 with its clutch teeth with the internal clutch teeth 81. When said clutch elements 85 and 86 are so interlocked conditions are established for a direct drive between the main power member thru the spline shaft and propeller shaft to the differential at the rear axle, the other transmission elements within the in constant mesh with countershaft gear 8|, must be positively coupled-to spline shaft 12 in order that the drive may be transmitted thru gears 11, 18, 8| and 19 to said spline shaft. The means for coupling gear 1.9 to the spline shaft comprise a dished or concave positive dog or toothed clutch element 89 rigid with said gear 19, and said positive dog or toothed element 86 slidable on the spline shaft. Said clutch element 86 is double ended, as shown, and is provided with external gear-like teeth 90 adapted to internal teeth 9| formed within the cavity of the clutch element 89. on gear 19..

Double ended sliding clutch element 86 hasacircumferential groove 92 about its middle in which yoke 68 engages in orderthat the clutch element v Clutch member I, 85 is dished or concaved and equipped with inter- 88 interlocking or spaces 94 for a purpose presently to be revealed. These groups or batteries of teeth are three in number in the illustrated embodiment. The clutch teeth 81, 88, 98 and 9| are preferably relatively fine and numerous, and their leading 5 ends are double inclined or tapered as at 93 to provide for intermeshing with as little clashing as possible. The tapered surfaces 93 of the teeth at the sides of spaces which merge into correspondingly taperedsurfaces 93' on the sides of 10 said spacesralso function as detent surfaces in a manner to be explained presently.

It is diflicult, especially for inexperienced or careless motor vehicle operators, to change from high to intermediate speed ratio or the reverse, by 15 releasing one pair of toothed positive coupling elements and directly interengaging another withportant characteristics named, and I have insured synchronous speeds before intermeshing the toothed elements by interposing a releasable conthe time permitted forcibly enough tobring the 45 ing a releasable connection between them such that meshing of the positive clutch element with 50 its'companion is resisted until synchronization has been accomplished. But instead of interposing a connection calculated-to release under a definite quantity of force, I have interposed a de-' portionto the inertia of the parts involved.

Referring now to the friction clutch elements by means of which equal rotative speeds ofthe two power transmittingmembers 'to be coupled tion clutch drum, is provided conical friction surface 98 adapted to be engaged frictionally with the conical surface '95 on the main clutch shaft 1|; an identical clutch drum is 75 adapted to be engaged frictionally with the conical surface 96 on gear 18. As these friction clutch drums are identical in structure and functionthe same reference characters are used to identify each and its parts.

Each clutch'drum 8.1 may havea bronze clutch;

shoe on whichthe internal, conical surface 98 is formed. The drum maybepressed from sheet steel in dished form with a flat bottom '99 the central portion of whichis removed to form a central hole so that the drum may engage overand of the central hole and enter into one or more of the grooves between the lands of the spline shaft.

Lugs Hill are of less circumferential extentthan said grooves and provide -fora positive .driving connection between the spline shaft and the clutch drum and alsolfor a limited relative rotary or angular movement. I have shown three of these lugs I60 for'each drum, but there may be one for each groove. or any lesser number adequate to afford the necessary strength.- The central-flat portion surroundingthe central hole is preferably a continuous ring connected to the outer zone or rim of the drum by radial spoke-like arms, IOI, which slant from the central ring to the end outer portions I02 which are flush with theback surface of the outerzone of the drum. The driun illustrated has three 7 such correspondingto the spaces between the groups or batteries of teeth in the toothed coupling element 86. Because of the described construction :of the drum the batteries of teeth 88 or 80' may pass beto eng e the companion tween the arms, llll teethof the mating clutch element on the other power transmission member when synchronous speeds of the two members have been attained.

Each clutchldrum. 91 may have a limitedaxial movement sufllcient to permit the conical friction surfaces to be pressed into driving engagement and be released. This movement is preferably very slight as it is desirable to have the internal conical.friction surface of the drum ridev on the oily external cooperating conical surface of the mating element when clutchelement 86 is in neutral for a reason that will presently; appear.

A stop, ring I03-limitstheretreat of reach drum t v thatthe conical surfaces separate only far enough to allow them from interengaging position so to ride one on the other with an oil film in between.-

The edges of'the portions I62 of arms I are provided with inclined detent surfaces IM; or it may, be said that the lateral walls of the spaces between the arms have inclined detent surfaces I04. These detent surfaces are preferably substan'ti'ally parallel, when in contact. with the inclined end faces 93, 935of the adjacent teeth 86 or 90 and side walls of the spaces 94 element 86 which constitute enacting detent elements, tent surfaces shall have such form that if forced axially into contact the force acting axially will be resolved into two forces one of whichis tangential to the circle in'which the detents revolve. The extentof rotary movement relative to the spline shaft of which each drum 6! is capable is sufficient to bring said coacting detent surfaces One or more I04 of the friction clutch drum arms equally spaced.

'tive clutch elements to slide together.

of clutch theint'ention being that the coacting .de-

there is any differential rotation between the spline shaft 18 and the main II or gear 18 by reason of the oil film between the mating conical surfaces, will'be dragged to one 5 extremity or the other of. their possiblerotary movement'on the spline shaft, so that under'such conditions ianaxiai 'thrust' upon the clutch ele'-' ment 86 will press thefriction surface'of one or the other drum into firm contact with its companion friction-surface. If with gears-in neutral, main clutch released and car coasting'so that spline shaft 12" is being driven by the car moving by inertia, it is desired to connect the'spline shaft directly withthe in- 15 termediate gear '19; which is now idling, together.

with the counter shaft gear-sand main clutch shaft 1|, the handle of hand lever 56 is moveclby the operator to the right andthen to the front according to'usual practice in American built motor cars. The described-movement'of the hand leverapplies an axial force, greater than that applied in shifting gears directly into mesh as shown herein with respect -tochanging to low or 'reverse. The resultingrearward axial movement .of toothed coupling forces the inclined detent surfaces 68 on the teeth adjoining one side or the other of each space 84 of the toothed coupling axially against the corresponding detent surfaces 81 on one side or the other of the arms JM; according to whether the gear "or thespline shaft 12 is rotating the faster. The force applied to oppose furtheradvance of the toothed'coupl'ing toward intermeshing position will thendepend upon the tangenttal force due to the inertia of gear I8, countershaft gears and main clutch shaft". If this force is greater than the operator can overcome he can-, not intermesh the toothed clutch'elements. The

pressure he applies in endeavoring to overcome 40 said tangential force presses the friction elements together; when the pressure is sufficient to'bring the gear 19 and spline shaft'substantially to v equal speeds the tangential force disappears and 1 continued pressure upon the hand lever can then 5 displace circumferentially the gear 18 and its dependent'elements owing to the'inclination of the detent surfaces, permitting the teeth of the posi- Moving the upper end of the hand lever rearward operates in the same manner to synchronize andcouple indirect drive.

In Fig. 1 there is shown between each stop ring 108 and drum 61, an annular spring I05 designed to exert an elastic force upon the drum which tends to press the internal conical friction face 88 thereof onto theexternal conical'friction face of its companion member. The force exerted by the spring need not be greater thanone or two .pounds; The function of the spring is to obtain such contact between the friction surfaces as will insure dragging 'ofthe drum to the limit of its angular movement on' the spline shaft in one sensewor the other dependent upon the relative speeds of the spline shaft and the member to be 55 coupled with it sons to set the detent surfaces'in axial alinement. "Ordinarily the drag of the oil vfilm between the friction surfaces is adequate for I this purpose without axial pressure, but the use of a spring as described assures the desired result.

Spring 105, as illustrated in Fig. 9 may be a ring of material such as steel having a plurality of elastic tongues I06 partially severed from the ring in a circumferential direction and pressed outward from the plane of the ring as shown. As

an alternative means for securing a drag between the friction surfaces adequate to set the .detent bevels in axial alinement a spring may be mount ed on the drum in the path ofmovement of the coupling element 86 as it moves toward intermeshing position, and be so disposedthat said coupling may contact with the spring during the initial portion of said movement, apply through it a relatively light pressure suflicient to obtain a degree of frictional engagement between the coacting conical surfaces of the frictionalrelements I insure alinement of the dethat is adequate to tent bevels, and then deform the spring and pass by it. In Figs. 7 and 8 a convenient form and mounting of a spring for the desired purpose is illustrated. A straight spring steel wire I! is inserted through alined holes drilled through the drum 9! at the positions I08. Notches I09 may be cut or formed in the drum to receive the ends of the wire, and these ends may be bent as at NO to hold the wire in place. The spaces between spokes or arms l0! of the drums may be formed with a rectanglrar enlargement H l across which. the wire extends along a chord of the drum circle. The middle of the wire IO'l-is disposed a distancev from the axis of the spline shaft somewhat less than the tooth crown radius of coupling 86, the teeth of which are rounded or beveled as at H2 so that these leading beveled ends may touch the wire during the initial portiontof the intermeshing movement of the coupling, spring the wire to one, side and pass on. There may be as many wires as there are spaces between arms.

In accordance trated and described my invention in the best forms now known to me; but I do not intend to be limited to the specific details of construction ofthe disclosure but only by the scope of the appended claims,

I claim: I t

l. The combination of two coaxial power transmitting members one of which includes a grooved shaft; a toothed positive clutch element keyed to and slidable on said grooved shaftya toothed positive clutch element fixed to the other power transmitting member; mating friction clutch elements respectively connected to be posi-' tively driven by the respective power transmitting members; one of said friction clutch elements provided with radial lugs engaging in the grooves of the grooved shaft so as tobe capable of limited relative rotary motion thereof with respect to said shaft; said last named friction clutch element having passages adapted to permit the teeth of the slidable positive clutch element to pass therethrough and engage the companion toothed clutch element; inclined detent surfaces ment is at either limit of its relative rotary move ment. v

2. A combination as defined in claim I wherein said friction clutch elements have coacting conical friction clutch surfaces one of whichis freely rotatable on the other when they are in non-driving position and means for limiting the releasing movementof thefriction clutch elements.

3. A combination as defined in claim 1 wherein said friction clutch elements have coacting conical friction clutchsurfaces one of which is freely rotatable on the other in non-driving position, and a stop on the grooved shaft to limit with the statutes I have illusaxial releasing movement of the friction clutch elementv which is driven positively by said shaft.

4. A combination as defined in claim 1 wherein the friction clutch element driven by the groved shaft comprises a centrally perforated ring-likepart surrounding the grooved shaft and arms radiating from the central ring-like part toward the frictional engaging surface leaving openings between the arms 'thru which the teeth of the slidable positive clutch element may pass. 10

5. The combination of two coaxial power transmitting members, one of which includes a splined shaft; a friction and a positive clutch element independently keyed to and movable axially of the spline shaft and positively driven thereby, said friction clutch element having means engaging between the splines to permit a limited rotary movement with respect to said spline shaft; a friction and positive clutch element fixed to the other power transmitting member; means for moving said slidable positive clutch element toward its companion member, cooperating detent surfaces on said axially movable friction and positive clutch elements'adapted to be brought into engagement by the axial movement of the positive clutch element toward its mating element whereby the friction clutch elements are pressed into engagement and the toothedclutch elements are prevented from engagement until the axial pressure exerted between the 'detent surfaces angularly displaces the axially movable friction clutch element relative to the axially movable toothed clutch element. v

6. A combination asdefined in claim 5 in which the axially movable friction clutch element comprises a dished drum having a ring-like central part surrounding the splineshaft, and radiating arrnsinclined from the ring-like part toward the slidable toothed clutch element, providing spaces therebetween; the fixed clutch element compris- 40 ing internal radiating teeth, and the sliding clutch element external radiating teeth arranged in equally spaced groups, the groups being separated by inclined grooves'of greaterdepth than the teeth, said inclined grooves and inclined radiating arms corresponding in number and width.

7. The combination transmitting members adapted to be positively ing to press the friction surfaces of said-friction mission member-between the stop ring and the coupled in driving relation, a friction and a positive coupling element separate friction and positive elements driven by th other member and axially movable to effect friction and positive coupling of said members in sequence; said last named friction element having openings therethru and separate defiectable spring wires disposed across said openings along chords of a circle struck from the center of said friction element, and said last named positive coupling element having a plurality of teeth adapted to deflect said spring wires and to pass thru said openings in order to first effect engagement of the friction coupling and thereafter engagement of the positive coupling.

10. A combination as defined in claim 9 in which the openings thru the friction element are separated by radial spoke-like formations; the separate defiectable spring wires are stretched across within said openings, and the axially movable positive coupling provided with groups of teeth, said groups being equal in number to said openings in the friction element and separated by spaces adapted to receive the spoke-like formations.

11. A combination as defined in claim 9 wherein the axially movable friction coupling element has a lost motion driving connection with the member by which it is driven, and detents on the driven by one member,

axially movable positive and friction coupling disposed in alinement when the friction coupling is at one end of its path of angular movement with respect to the member by which it is driven.

12} The combination of two coaxial power 5 transmitting members one of which includes a grooved shaft; a toothed positive clutch element slidable but not rotatable on said shaft; a toothed positive clutch element fixed to the other power transmitting member; two friction clutch elements respectively connected to be positively driven by the respective power transmitting members, one of said friction clutch elements having radial lugs engaging in the grooves of the grooved shaft so as to be capable of limited rela- 15 tive rotary and axial movement with respect to said grooved shaft; said last named friction clutch element having passages adapted to permit the teeth of the slidable positive clutch element to pass therethrough and engage the teeth of the companion positive clutch element; coopcrating detent surfaces at the edges of the passages through said last named. friction clutch element, and on the slidable positive clutch element, said detent surfaces being disposed in alinement when the friction clutch element is at either limit of its rotary movement relative to the shaft.

EARL A. THOMPSON. 

